Nixon went ahead in the summer of 1974 to hold a summit with Brezhnev in Moscow, but his days in the White House were numbered and he resigned in August.
The relationship between Washington and Moscow went on hold until the new administration of President Gerald Ford gathered momentum.
While Nixon was a firm adherent of U.S. strength he was opposed to brinkmanship in dealing with the Soviet Union, Dobrynin reported to Moscow in 1969, at the start of a unique personal relationship with Washington.
The State Department historical documents portrayed Nixon as not counting on the use of force. Quoting from an urgent telegram Dobrynin sent to Moscow, sizing up the new president, differences were too deep to bridge completely.
But, Dobrynin told the Soviet foreign ministry in his cable that ''the new president is opposed to methods of brinkmanship in relations with the USSR, since he believes that both our countries have at their disposal sufficient nuclear missiles to annihilate each other many times over.''
By all indications, Dobrynin told Moscow, Nixon ''will pursue a pragmatic course that envisages negotiations with the Soviet Union in cases where it serves U.S. interests and where it is possible to reach a compromise.''
Agreements to ban biological weapons and to limit the arsenals of long-range missiles are among the understandings that emerged from the complicated U.S.-Soviet relationship.
Also, an agreement was forged in 1971 between the two superpowers and also Britain and France to reduce tensions over then-divided Berlin.
On the other hand, Nixon sent a carrier force into the Indian Ocean in December 1971 to signal the Soviets to restrain their ally, India, in the brief war with Pakistan that created Bangladesh.
Historian David Geyer, the principal U.S. compiler for the project, said Wednesday that it reflects ''an unprecedented partnership between the two governments to document an exchange of views at a high level, particularly at an important period of the Cold War.''
The real value to scholars is found in the Russian documents dealing with detente between the superpowers that were declassified for the historical project and made available to the public as never before, Geyer said.
''The documents also give readers and scholars a different view on foreign policy from the perspective of the other superpower,'' Geyer said.
Dobrynin met occasionally and separately with Nixon but conducted most foreign policy business through a unique channel to Henry Kissinger, the national security adviser and beginning in 1973 secretary of state.
The channel was Nixon's idea. ''He told me there were a number of matters _ crucial, urgent and confidential ones — which are better discussed by heads of state directly through their confidants, bypassing the cumbersome bureaucratic machinery'' which sometimes leaks to the press, Dobrynin wrote.
In a foreword to the documents on the era known as detente, Dobrynin said that ''without that channel it could hardly have been possible to reach many key agreements in a timely manner or to eliminate dangerous tensions that periodically arose.''
He cited disputes over Berlin, Cuba, the Middle East and arms control.